SUBSTITUTION OF A SINGLE AMINO-ACID RESIDUE IS SUFFICIENT TO ALLOW THE HUMAN AMPHOTROPIC MURINE LEUKEMIA-VIRUS RECEPTOR TO ALSO FUNCTION ASA GIBBON APE LEUKEMIA-VIRUS RECEPTOR

We have previously reported the unique properties of a receptor for am photropic murine leukemia viruses (A-MuLVs) expressed on Chinese hamst er E36 cells (C. A. Wilson, K. B. Farrell, and M. V. Eiden, J. Virol. 68:7697-7703, 1994). This receptor, HaPiT2 (formerly designated EAR), in contrast to the human form of the A-MuLV receptor (PiT2), functions as a receptor not only for A-MuLVs but also for gibbon ape leukemia v irus (GALV). Comparison of the deduced amino acid sequences of the HaP iT2 and PiT2 proteins suggested that differences in the amino acid com position of the extracellular region(s) of the hamster and human prote ins account for their functional differences, We substituted extracell ular regions of HaPiT2 for those of PiT2 to map the region of the HaPi T2 protein required for GALV receptor function, Only those PiT2-HaPiT2 chimeric receptors containing the fourth and fifth extracellular regi ons of HaPiT2 functioned as GALV receptors, We have now determined tha t the substitution of a single amino acid residue, glutamic acid, for the lysine residue at position 522 in the fourth extracellular region of the PiT2 protein is sufficient to render PiT2 functional as a GALV receptor.